Nanotube enhancement of interlaminar performance for a composite component

ABSTRACT

A composite article including a multiple of composite layers impregnated with a polymer matrix; and a nanotube material that facilitates a mechanical interlock between at least two of the multiple of composite layers. A method of manufacturing a composite article including a multiple of composite layers within a polymer matrix; and distributing a nanotube material between at least two of the multiple of composite layers to facilitate a mechanical interlock between the at least two of the multiple of composite layers adjacent an otherwise relatively low strength interlaminar interface region of the composite article.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/886,480, filed Oct. 19, 2015.

BACKGROUND

The present disclosure relates to polymer composite materials and, moreparticularly, relates to enhancement of the interlaminar performancethereof.

Polymer matrix composite materials with carbon fiber reinforcement offersignificant stiffness-to-weight and strength-to-weight advantages.However, due to their relatively low through-thickness, or interlaminarinterface properties, the application of these composite materials tocomplex aero-engine components with angle bend features such as flanges,L-sections, T-sections, sharp diameters, etc., may be a challenge,especially when the composite material is stressed in thethrough-thickness direction.

SUMMARY

A composite article according to one disclosed non-limiting embodimentof the present disclosure can include a multiple of composite layersimpregnated with a polymer matrix; and a nanotube material thatfacilitates a mechanical interlock between at least two of the multipleof composite layers.

A further embodiment of the present disclosure may include, wherein thenanotube material includes carbon nanotubes.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes glass nanotubes.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes nanotubes that aregenerally non-aligned.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material is applied onto at least oneprepreg layer of the multiple of composite layers.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes nanotubes that arealigned.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes nanotubes that forma lattice structure.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes multiple individualnanotubes.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes nanotubes that areunilaterally oriented.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes nanotubes that areunilaterally oriented in a manner to be transverse to at least one ofthe multiple of composite layers.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material is located adjacent an anglebend feature of the composite article.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material is located adjacent arelatively high stressed through-thickness region of the compositearticle.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material is located in an otherwiserelatively low interlaminar interface region of the composite article.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes nanotubes that forma thermal transmission path from a relatively high temperature region toa relatively low temperature region of the composite article.

A composite article according to another disclosed non-limitingembodiment of the present disclosure can include a multiple of compositelayers impregnated with a polymer matrix that forms an angle bendfeature; and a nanotube material that facilitates a mechanical interlockbetween at least two of the multiple of composite layers adjacent theangle bend feature.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes nanotubes that aregenerally non-aligned.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the nanotube material includes nanotubes that aregenerally aligned.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the angle bend feature forms an interface adjacentan airfoil section of the composite article.

A method of manufacturing a composite article according to anotherdisclosed non-limiting embodiment of the present disclosure can includea multiple of composite layers within a polymer matrix; and distributinga nanotube material between at least two of the multiple of compositelayers to facilitate a mechanical interlock between the at least two ofthe multiple of composite layers adjacent an otherwise relatively lowinterlaminar interface region of the composite article.

A further embodiment of any of the embodiments of the present disclosuremay include, distributing the nanotube material on a pre-impregnatedmaterial layer, the nanotube material adjacent an otherwise relativelylow interlaminar interface region of the composite article.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, the following descriptionand drawings are intended to be exemplary in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features will become apparent to those skilled in the art fromthe following detailed description of the disclosed non-limitingembodiments. The drawings that accompany the detailed description can bebriefly described as follows:

FIG. 1 is an exploded view of vane cluster with a single representativevane illustrative of a composite article;

FIG. 2 is a sectional view of the composite article;

FIG. 3 is an enlarged sectional view of the composite article accordingto one disclosed non-limiting embodiment;

FIG. 4 is an enlarged sectional view of the composite article accordingto one disclosed non-limiting embodiment;

FIG. 5 is an enlarged sectional view of the composite article accordingto one disclosed non-limiting embodiment;

FIG. 6 is an expanded view of a vane with a nanotube material paththerethrough;

FIG. 7 is a method of manufacturing a composite article with a nanotubematerial.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a composite article 20 fabricated froma polymer composite material. The composite article 20 in one exampleincludes an angle bend feature 22 that may be relatively highly stressedin the through-thickness direction. In this example, the compositearticle 20 is a stator vane for use in a gas turbine engine and theangle bend feature 22 may be a transition region 24 between a vaneplatform 26 and an airfoil section 28 of the composite article 20. Itshould be appreciated that although a stator vane example is illustratedherein, other aerospace components, aircraft structures, as well as awide variety of applications outside the aerospace industry, which maybe fabricated from polymer composite materials that have a local regionof high interlaminar stress or require impact resistance will benefitherefrom. In other words any area with a relatively low strengthinterlaminar interface.

With reference to FIG. 2, the composite article 24 has a laminateconstruction manufactured of individual composite layers 30 and apolymer matrix 40 reinforced with a nanotube material 50. The polymermatrix 40 is impregnated into the composite layers 30 and the nanotubematerial 50 is inserted between two adjacent composite layers 30 suchthat during processing the nanotube material 50 may interpenetrate thelayers 30. It should be appreciated that although the nanotube material50 is schematically illustrated as between two layers 30, the nanotubematerial 50 may be located within or upon multiple polymer compositelayers 30. The composite article 20 can be fabricated by a wide varietyof fabrication techniques including, but not limited to, autoclavecuring, out-of-autoclave curing, compression molding, resin transfermolding and vacuum assisted resin transfer molding, which for example,facilitate impregnation of the individual composite layers 30 and thepolymer matrix 40.

The composite layers 30 are stacked, shaped and cured according tovarious practices to produce the laminate construction. It should beappreciated that various numbers and arrangements of composite layers 30will benefit herefrom irrespective of that schematically illustrated. Inaddition, a core material, such as a lightweight foam or honeycombpattern material, could be incorporated into the laminated compositestructure, as is common for aircraft engine nacelle components such asengine inlets, thrust reversers, cowlings, as well as otheraerostructures.

The polymer matrix 40 within the composite layer 30 merges with thefibers of the composite layer 30 and contributes to the structuralintegrity and other physical properties of the composite article 20.Materials for the polymer matrix 40 may include various materials thatexhibit temperature and impact resistance suitable for withstandingForeign Object Damage and other types of damage to which the compositearticle 20 is likely to be subjected. Example polymer matrix 40materials include suitable resin systems such as thermoset andthermoplastic materials, i.e., epoxies, bismaleimides, polyimides,polyetheretherketone (PEEK), poly(aryl) etherketoneketone (PEKK) andpolyphenylene sulfide (PPS), though the use of other matrix materials isforeseeable.

With reference to FIG. 3, the nanotube material 50 may include carbon orglass nanotubes 52. The nanotube material 50 may be located locally atthe interfaces between composite layers 30 such as in and around theangle bend regions 22. The nanotube material 50 facilitates a mechanicalinterlock at the local region of its application, such as the relativelyweak interlaminar regions of the composite lay-up to enhance strengthand fatigue capability of the composite article 20.

In one embodiment, the nanotube material 50 can be applied to thesurface of a prepreg material layer which would result in the nanotubesresiding in the interface region between layers. However, there aremultiple approaches for nanotube material 50 integration such that thenanotube material 50 can reside in, for example, exclusively betweenlayers or within and between layers i.e. in all resin locations.

The nanotube material 50 can be applied in various manners, includingbut not limited to, 2D fabrics and tapes, multi-layered braidedstructures, hybrid structures such as 3D woven cores with fabric skins,as well as pre-impregnated material forms and dry, or tackified,material forms. In one embodiment, the nanotube material 50 may begenerally non- aligned such that the nanotube material is relativelyrandomly distributed. For example, the nanotubes 52 may be mixed-in withthe polymer matrix 40 and/or sprinkled onto a particular composite layer30 where the interlaminar stresses are expected to be relatively high.

The nanotube material 50 can be applied selectively upon one or morecomposite layers 30 where the interlaminar stresses are expected to behigh. For example, the nanotube material 50 may be locally spread, i.e.,“sprinkled” in a region between particular composite layers 30.Alternately, or in addition, the nanotube material 50 may be distributedonto the entirety of one or more composite layers 30 to facilitateballistic resistance to form, for example, a blade containment belt, afan blade, or other ballistic resistant structure.

With reference to FIG. 4, in another embodiment, the nanotube material50A may be arranged in an aligned configuration. In one example, thenanotube material 50 may include numerous nanotubes 52 that are arrangedto provide a “forest” of nanotubes 52 that are generally unilaterallyaligned one to another so as to penetrate into the adjacent compositelayers 30 to provide a mechanical interlock. That is, the nanotubes 52are generally unilaterally oriented in a manner to be transverse to theadjacent composite layers 30. The nanotubes 52 may, for example, beapplied, e.g., grown upon the substrate, and or directly applied to oneor more of the composite layers 30 via a chemical vapor depositionprocess.

In still another embodiment, as shown in FIG. 5, the nanotube material50B includes nanotubes 52 that are arranged with respect to thesubstrate to form a “crisscross” or other lattice structure tofacilitate a mechanical interlock. That is, the nanotubes 52 arearranged in a pattern other than a “forest” type orientation.

With reference to FIG. 6, in another embodiment, the nanotube material50 may be located along a path 60 (illustrated schematically) in thecomposite article 20. The path 60 may, for example, provide a thermaltransmission path from a relatively high temperature area such as theairfoil 28 to a relatively low temperature area, such as the platform26, to facilitate thermal management. That is, the nanotube material 50can facilitate thermal transmission in addition to the mechanicalinterlock.

With reference to FIG. 7, one disclosed non-limiting embodiment of amethod 100 to manufacture the composite article 20 initially includesformation of the nanotube material 50 such as via a “forest” of alignednanotubes 52 that may be manufactured on a substrate material (step110). Next, the nanotubes 52 are transferred from the substrate to thesurface of a traditional pre-impregnated material (step 120). It shouldbe appreciated that although a single pre-impregnated material isdisclosed, multiple layers may include the nanotubes 52. Next,individual plies from the prepreg layup for manufacture of the compositecomponent 20 are cut and stacked with the nanotube impregnatedpre-impregnated material incorporated therein (step 130). As described,the nanotube material 50 may be locally applied at the interfacesbetween composite layers 30 in and around, for example, the angle bendregions 22. The ply lay-up is then cured (step 140). For example, thecuring may be performed with standard composite fabrication techniquesto form the composite article 20.

The utilization of the nanotube material 50 increases interlaminarstrength and fatigue properties with potentially lower manufacturingcosts through the use of relatively less expensive polymer resins ratherthan relatively higher cost toughened polymers or other costly means tootherwise enhance interlaminar properties. The utilization of thenanotube material 50 may also facilitate the use of polymer compositesin regions and applications that were previously limited due to lowinterlaminar properties of the material to increase performance andenable more widespread use of light-weight polymer composite materialsas the nanotube material 50 may relatively facilitate reduction inseparation between the composite layers 30.

The use of the terms “a,” “an,” “the,” and similar references in thecontext of description (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or specifically contradicted bycontext. The modifier “about” used in connection with a quantity isinclusive of the stated value and has the meaning dictated by thecontext (e.g., it includes the degree of error associated withmeasurement of the particular quantity). All ranges disclosed herein areinclusive of the endpoints, and the endpoints are independentlycombinable with each other. It should be appreciated that relativepositional terms such as “forward,” “aft,” “upper,” “lower,” “above,”“below,” and the like are with reference to normal operational attitudeand should not be considered otherwise limiting.

Although the different non-limiting embodiments have specificillustrated components, the embodiments of this invention are notlimited to those particular combinations. It is possible to use some ofthe components or features from any of the non-limiting embodiments incombination with features or components from any of the othernon-limiting embodiments.

It should be appreciated that like reference numerals identifycorresponding or similar elements throughout the several drawings. Itshould also be appreciated that although a particular componentarrangement is disclosed in the illustrated embodiment, otherarrangements will benefit herefrom.

Although particular step sequences are shown, described, and claimed, itshould be understood that steps may be performed in any order, separatedor combined unless otherwise indicated and will still benefit from thepresent disclosure.

The foregoing description is exemplary rather than defined by thelimitations within. Various non-limiting embodiments are disclosedherein, however, one of ordinary skill in the art would recognize thatvarious modifications and variations in light of the above teachingswill fall within the scope of the appended claims. It is therefore to beunderstood that within the scope of the appended claims, the disclosuremay be practiced other than as specifically described. For that reasonthe appended claims should be studied to determine true scope andcontent.

1-18. (canceled)
 19. A method of manufacturing a composite article,comprising: a multiple of composite layers within a polymer matrix; anddistributing a nanotube material between at least two of the multiple ofcomposite layers to facilitate a mechanical interlock between the atleast two of the multiple of composite layers adjacent an otherwiserelatively low strength interlaminar interface region of the compositearticle.
 20. The method as recited in claim 19, further comprisingdistributing the nanotube material on a pre-impregnated material layer.21. The method as recited in claim 19, wherein the nanotube material islocated adjacent an angle bend feature of the composite article.
 22. Themethod as recited in claim 21, wherein the angle bend feature of thecomposite article is between an airfoil region and a platform region,the airfoil region transverse to the platform region.
 23. A method ofmanufacturing a composite article, comprising: a multiple of compositelayers within a polymer matrix; and distributing a nanotube materialbetween at least two of the multiple of composite layers to facilitate amechanical interlock between the at least two of the multiple ofcomposite layers adjacent an angle bend feature of the compositearticle.
 24. The method as recited in claim 23, wherein the angle bendfeature of the composite article is between an airfoil region and aplatform region, the airfoil region transverse to the platform region.